Just like the other commenter, the Outer Wilds main motif (travelers) makes me emotional because of how good the game was. Disco Elysium also has had an amazing soundtrack, with the main BGM faintly using sounds from the final song, which made it really cathartic for me.
Ultrakill deserves a lot of praise, especially for the P-2 music (youtu.be/MG5L-1pI8bI). It works perfectly for how intense the level is, and it’s absolutely nuts that the game still manages to up the ante after you’ve perfected every single other level. I’ve listened to this type of music quite often before, but I’ve never felt it in my blood and muscles before playing that level.
When judged on the music alone though, Hotline Miami (1) and Furi have to take the cake. Both soundtracks are just iconic, and easily stand out on their own.